A modern computing apparatus includes many different components, otherwise known as entities, (the word “component” and “entity” is used here to describe essentially any discrete functional element of a computing platform, including either a piece of hardware, a piece of software or a piece of firmware), most of which are standardized and can be upgraded. Alternatively, the use of computer entity can refer to a computer platform comprising a plurality of components.
EP patent application 99301100.6 describes the use of a Trusted Component (‘TC’), also known as a trusted device (TD), to enable verification of the integrity of computing apparatus by the reliable measurement and reliable reporting of integrity metrics. This enables the verification of the integrity of computer apparatus by either a local user or a remote entity. EP patent application 99301100.6 describes a general method of reporting integrity metrics and verifying the correctness of the integrity of computing apparatus by comparing reported values of metrics with verified values of metrics. This solution allows an apparatus' challenger (where a challenger is defined as a local or remote device possibly operating on behalf of a human user) to challenge the trusted device in order to check the integrity of one or more particular component. The trusted device responds to the challenge by sending a signed report of the one or more particular components. The report includes information about the components, such as the model of a component, the manufacturer of a component, the version of a component, upgraded data and so on. After receiving the report, the challenger makes a decision on whether or not to trust a particular component, and furthermore after checking a number of selected functional components, the challenger will make a decision whether or nor to trust the computing apparatus.
One useful feature, which has not been covered by this prior art solution, is how the challenger of the computing apparatus is able to make its own decision easily and how those decisions can be dealt with in a flexible manner.
It is desirable to improve this situation.